The plus–minus sign, ±, is a mathematical symbol with multiple meanings: In mathematics, it generally indicates a choice of exactly two possible values, one of which is obtained through addition and the other through subtraction. Wikipedia

A symbol used in mathematics and related fields Wikipedia Disambiguation

Mathematical symbol Wikidata

The symbol ±, meaning "plus or minus", used to indicate the precision of an approximation (as in "The result is 10 ± 0.3", meaning the result is anywhere in the inclusive range from 9.7 to 10.3), or as a convenient shorthand for a quantity with two possible values of opposing sign and identical magnitude (as in "The roots of the equation x2 - 4 = 0 are ±2"). Wiktionary